[STM32 learning] (17) STM32 realizes LCD12864 display serial implementation

Source download link ：(1 Bar message ) STM32 Realization LCD12864 Show - Serial implementation - Telecommunication document resources -CSDN download

About LCD12864 Information , Let me post a little for you first .

Pin definition when working in parallel mode ：

PIN1------------------GND    Power on -, In general 0V（ Depending on the specific LCD model ）

PIN2------------------ Power on +, In general 5V（ Depending on the specific LCD model ）

PIN3------------------ Contrast adjustment end ,VDD and GND Connect both ends of the adjustable resistor , The middle tap is connected to V0

PIN4------------------RS Instructions / Data selection

PIN5------------------R/W Reading and writing choices

PIN6------------------E, Enable signal

PIN7------------------D0, Data bits 0

PIN8------------------D1, Data bits 1

PIN9------------------D2, Data bits 2

PIN10------------------D3, Data bits 3

PIN11------------------D4, Data bits 4

PIN12------------------D5, Data bits 5

PIN13------------------D6, Data bits 6

PIN14------------------D7, Data bits 7

PIN15------------------PSB  parallel ：PSB=1, Can connect VCC, Serial ：PSB=0, In general GND

PIN16------------------NC, Not connected

PIN17------------------~RST, Module reset , Not connected

PIN18------------------NC, Not connected

PIN19------------------LED+, Backlight +, In general 5V（ Depending on the specific LCD model ）

PIN20------------------LED-, Backlight -, In general GND

Pin definition when working in serial mode ：

PIN1------------------GND    Power on -, In general 0V（ Depending on the specific LCD model ）

PIN2------------------ Power on +, In general 5V（ Depending on the specific LCD model ）

PIN3------------------ Contrast adjustment end ,VDD and GND Connect both ends of the adjustable resistor , The middle tap is connected to V0

PIN4------------------RS（CS）, Chip selection

PIN5------------------R/W（SID）, data

PIN6------------------E（SCK）, pulse

PIN7------------------NC, Not connected

PIN8------------------NC, Not connected

PIN9------------------NC, Not connected

PIN10------------------NC, Not connected

PIN11------------------NC, Not connected

PIN12------------------NC, Not connected

PIN13------------------NC, Not connected

PIN14------------------NC, Not connected

PIN15------------------PSB  parallel ：PSB=1, Can connect VCC, Serial ：PSB=0, In general GND

PIN16------------------NC, Not connected

PIN17------------------~RST, Module reset , Not connected

PIN18------------------NC, Not connected

PIN19------------------LED+, Backlight +, In general 5V（ Depending on the specific LCD model ）

PIN20------------------LED-, Backlight -, In general GND

12864 LCD parallel port driver is used more , But considering that sometimes SCM or MCU Of IO The serial drive method can be used when the port is limited . Here are 12864 LCD serial sequence diagram , Now let's analyze it according to this figure 12864 Implementation of serial timing , Only by really understanding the sequence diagram can we really understand the principle of serial transmission .

It can be seen from the figure that serial transmission requires CS,SCLK,SID Three signal lines , But because of CS It's high level effective , So you can also CS Long connect high level , Then only two wires are needed OK 了 , Of course, when using 12864 In serial mode ,PSB The pin must be connected to the low level , Reset RST The pin can be suspended , because 12864 There is an internal power on reset circuit .

Because data is transmitted in one byte 8bits In units of , So the function implementation of transferring one byte is posted below

As can be seen from the sequence diagram , To transmit a byte of data completely , It takes three times to transmit , That is, three bytes need to be transmitted , These three bytes are ： Command control word , The upper four bits of bytes + Four lower 0 Composed byte , The lower four bits of bytes + Senior four 0 Composed byte .

                                                                     Command control word 11111RWRS0

RW Represents reading or writing LCD , by 0 Representative writing , by 1 Representative reading .RS Represents write command or data , by 0 For writing commands , by 1 For writing data , rest 6 Bit fixation . So suppose you want to write data to the LCD , You must first send 11111010, Write a command and send 11111000.

The following is the specific implementation of the program , This is the key ！
Hardware ：

Single chip model ：STM32L052K8*      In fact, no matter which MCU achieves the same effect

LCD model ：LCD12864

connection ：

PA0  Pick up    RS（CS）

PA1  Pick up    R/W（SID）

PA2  Pick up    E（SCK）

PA3  Pick up    RST    You can skip this , Suspended or connected to high level （VCC）, The LCD has the function of power on reset , See your own implementation needs to add

lcd12864.c

#include "lcd12864.h"
#include "main.h"
/******************************************
* name ：void Write_8bits(uint8_t W_bits)
* function ： According to the serial communication protocol of LCD , send data 
* Input ：W_bits
* Output ： nothing 
*******************************************/
 
void Write_8bits(uint8_t W_bits)
{
	uint8_t i,Temp_data;
	for(i=0; i<8; i++)// Move eight times in total , You can put the 8bits All the data is transmitted 
	{
		Temp_data = W_bits;
		Temp_data <<= i;// Move the data left in turn 
		if((Temp_data&0x80)==0)  // Judge whether the corresponding bit is 0
		{
			HAL_GPIO_WritePin(SID_GPIO_Port,SID_Pin,GPIO_PIN_RESET);
			HAL_GPIO_WritePin(CLK_GPIO_Port,CLK_Pin,GPIO_PIN_RESET);	//SCLK = 0;// Transmit data on the falling edge of the clock 
			HAL_GPIO_WritePin(CLK_GPIO_Port,CLK_Pin,GPIO_PIN_SET);		// SCLK = 1;// Set high level , Prepare for the next transmission 
		}
		else         // The corresponding bit is 1
		{
			HAL_GPIO_WritePin(SID_GPIO_Port,SID_Pin,GPIO_PIN_SET);		//SID = 1;
			HAL_GPIO_WritePin(CLK_GPIO_Port,CLK_Pin,GPIO_PIN_RESET);	//SCLK = 0;// Transmit data on the falling edge of the clock 
			HAL_GPIO_WritePin(CLK_GPIO_Port,CLK_Pin,GPIO_PIN_SET);		// SCLK = 1;// Set high level , Prepare for the next transmission 
		}
	}
}

 
/****************************************
* name ：void W_1byte(uint8_t RW, uint8_t RS, uint8_t W_data)
* function ： Write serial data , according to RW RS Configuration of , Determine whether to transmit commands or data 
* Input ：uint8_t RW, uint8_t RS, uint8_t W_data
* Output ： nothing 
******************************************/
void W_1byte(uint8_t RW, uint8_t RS, uint8_t W_data)
{ 
	uint8_t H_data,L_data,S_ID = 0xf8;  //11111RWRS0
	if(RW == 0)
	{
		S_ID &=~ 0x04;
	}
	else     //if(RW==1)
	{
		S_ID |= 0X04;
	}
	if(RS == 0)
	{
		S_ID &=~ 0x02;
	}                                                                                                                               
	else     //if(RS==1)
	{
		S_ID |= 0X02;
	}
	// The above command words are combined according to the read-write command and whether to send data or command 
	H_data = W_data;
	H_data &= 0xf0;   // Shielding is low 4 A data 
	L_data = W_data;    //xxxx0000 Format 
	L_data &= 0x0f;   // High shielding 4 A data 
	L_data <<= 4;   //xxxx0000 Format 
	HAL_GPIO_WritePin(CS_GPIO_Port,CS_Pin,GPIO_PIN_SET);	//CS = 1;  Can send when 
	Write_8bits(S_ID);   // Send command word S_ID
	Write_8bits(H_data); // send out H_data
	Write_8bits(L_data); // send out L_data
	HAL_GPIO_WritePin(CS_GPIO_Port,CS_Pin,GPIO_PIN_RESET);	//CS = 0;  Can send when 
} 

 
/*****************************************
* function ：lcdinit()
* function ： Initialization function 
* Input ：cmdcode
* Output ： nothing 
*****************************************/
 
void lcdinit(void)
{
	
	HAL_Delay(10);
	W_1byte(0,0,0x30);// Feature set  8 Bit data , Basic instructions ;
	HAL_Delay(10);
	//W_1byte(0,0,0x02); // Address homing 
	//HAL_Delay(10);
	//W_1byte(0,0,0x06); // Move the cursor and display right one bit 
	//HAL_Delay(10);
	W_1byte(0,0,0x0c); // Display state  ON, The cursor OFF, The irony OFF
	HAL_Delay(10);
	W_1byte(0,0,0x01);  // Clear the display 
	HAL_Delay(10);
}
 
 

 
/******************************************
* name ：void LCD_Wmessage(uint8_t* message,uint8_t address)
* function ： towards LCD12864 Write a row of data in （ Because you can't send only one byte of data at a time ）
* Input ：uint8_t* message,uint8_t address
* Output ： nothing 
******************************************/
 
void LCD_Wmessage(uint8_t* message,uint8_t address)
{
	W_1byte(0, 0, address);
	while(*message>0)// This judgment is crucial , Judge whether your content has been sent 
	{
		W_1byte(0,1,*message); // Kernel or send byte function 
		message++; // The pointer works well ..
	}
}

lcd12864.h

#include "main.h"

#define			LINE1		0x80 // The starting address of the first line , The same below 
#define			LINE2 		0x90
#define			LINE3 		0x88
#define			LINE4 		0x98

void Write_8bits(uint8_t W_bits);
void W_1byte(uint8_t RW, uint8_t RS, uint8_t W_data);
void lcdinit(void);
void LCD_Wmessage(uint8_t *message,uint8_t address);

main.c

int main(void)
{
  /* USER CODE BEGIN 1 */
	uint8_t dis3[]={" abed, I see a silver light ,"};
	uint8_t dis4[]={" The frost on the ground ,"};
	uint8_t dis5[]={" look at the bright moon ,"};
	uint8_t dis6[]={" Bow your head and think of your hometown ."};
  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
	MX_GPIO_Init();
  /* USER CODE BEGIN 2 */
	lcdinit();
  /* USER CODE END 2 */
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
	LCD_Wmessage(dis3,LINE1);  
	LCD_Wmessage(dis4,LINE2);
	LCD_Wmessage(dis5,LINE3);
	LCD_Wmessage(dis6,LINE4);
    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

The effect is as follows ：

Code download link ：(1 Bar message ) STM32 Realization LCD12864 Show - Serial implementation - Telecommunication document resources -CSDN download